package com.youbug.mall.seckill.service.impl;

import com.alibaba.csp.sentinel.Entry;
import com.alibaba.csp.sentinel.SphU;
import com.alibaba.csp.sentinel.annotation.SentinelResource;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import com.alibaba.fastjson.JSON;
import com.baomidou.mybatisplus.core.toolkit.IdWorker;
import com.google.common.collect.Lists;
import com.youbug.common.config.FallbackClass;
import com.youbug.common.to.PmsSkuInfoTo;
import com.youbug.common.to.SeckillSessionWithSkusTo;
import com.youbug.common.to.UmsMemberTo;
import com.youbug.common.to.mq.SeckillOrderTo;
import com.youbug.common.vo.R;
import com.youbug.mall.seckill.feign.ISeckillCouponFeignService;
import com.youbug.mall.seckill.feign.ISeckillProductFeignService;
import com.youbug.mall.seckill.interceptor.SeckillInterceptor;
import com.youbug.mall.seckill.service.ISeckillService;
import com.youbug.common.to.SeckillSkuRedisTo;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RSemaphore;
import org.redisson.api.RedissonClient;
import org.springframework.amqp.rabbit.core.RabbitTemplate;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.BoundHashOperations;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Service;
import org.springframework.util.CollectionUtils;
import org.springframework.util.StringUtils;

import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.util.Date;
import java.util.List;
import java.util.Set;
import java.util.UUID;
import java.util.concurrent.TimeUnit;
import java.util.regex.Pattern;
import java.util.stream.Collectors;
@Slf4j
@Service
public class SeckillServiceImpl implements ISeckillService {

    @Autowired
    private StringRedisTemplate redisTemplate;
    @Autowired
    private ISeckillCouponFeignService seckillCouponFeignService;
    @Autowired
    private ISeckillProductFeignService productFeignService;
    @Autowired
    private RedissonClient redissonClient;
    @Autowired
    private RabbitTemplate rabbitTemplate;

    private final String SESSION__CACHE_PREFIX = "seckill:sessions:";

    private final String SECKILL_CHARE_PREFIX = "seckill:skus";

    private final String SKU_STOCK_SEMAPHORE = "seckill:stock:";    //+商品随机码

    @Override
    public void uploadSeckillSkuLatest3Days() {
    //1、扫描最近三天的商品需要参加秒杀的活动
      R<List<SeckillSessionWithSkusTo>> result = seckillCouponFeignService.getLates3DaySession();

      if(result.getCode()==R.SUCCESS){

          List<SeckillSessionWithSkusTo> sessionData = result.getData();

          saveSessionInfos(sessionData);

          saveSessionSkuInfo(sessionData);
      }
    }

    /**
     * 缓存秒杀活动信息
     * @param sessions
     */
    private void saveSessionInfos(List<SeckillSessionWithSkusTo> sessions) {
        if(CollectionUtils.isEmpty(sessions)){return;}

        sessions.stream().forEach(session -> {

            //获取当前活动的开始和结束时间的时间戳
            long startTime = session.getStartTime().toInstant(ZoneOffset.of("+0")).toEpochMilli();
            long endTime = session.getEndTime().toInstant(ZoneOffset.of("+0")).toEpochMilli();
            //存入到Redis中的key
            String key = SESSION__CACHE_PREFIX + startTime + "_" + endTime;

            //判断Redis中是否有该信息，如果没有才进行添加
            Boolean hasKey = redisTemplate.hasKey(key);
            //缓存活动信息
            if (!hasKey) {
                //获取到活动中所有商品的skuId
                List<String> skuIds = session.getRelationSkus().stream()
                        .map(item -> item.getPromotionSessionId() + "-" + item.getSkuId().toString()).collect(Collectors.toList());
                redisTemplate.opsForList().leftPushAll(key,skuIds);
            }
        });
    }

    /**
     * 缓存秒杀活动所关联的商品信息
     * @param sessions
     */
    private void saveSessionSkuInfo(List<SeckillSessionWithSkusTo> sessions) {
        if(CollectionUtils.isEmpty(sessions)){return;}

        sessions.stream().forEach(session -> {
            //准备hash操作，绑定hash
            BoundHashOperations<String, Object, Object> operations = redisTemplate.boundHashOps(SECKILL_CHARE_PREFIX);
            session.getRelationSkus().stream().forEach(seckillSkuVo -> {
                //生成随机码
                String token = UUID.randomUUID().toString().replace("-", "");
                String redisKey = seckillSkuVo.getPromotionSessionId().toString() + "_" + seckillSkuVo.getSkuId().toString();
                if (!operations.hasKey(redisKey)) {

                    //缓存我们商品信息
                    SeckillSkuRedisTo redisTo = new SeckillSkuRedisTo();
                    Long skuId = seckillSkuVo.getSkuId();
                    //1、先查询sku的基本信息，调用远程服务
                    R<PmsSkuInfoTo> info = productFeignService.getSkuInfo(skuId);
                    if (info.getCode() == R.SUCCESS) {
                        PmsSkuInfoTo skuInfo = info.getData();
                        redisTo.setSkuInfo(skuInfo);
                    }

                    //2、sku的秒杀信息
                    BeanUtils.copyProperties(seckillSkuVo,redisTo);

                    //3、设置当前商品的秒杀时间信息
                    redisTo.setStartTime(session.getStartTime().toInstant(ZoneOffset.of("+0")).toEpochMilli());
                    redisTo.setEndTime(session.getEndTime().toInstant(ZoneOffset.of("+0")).toEpochMilli());

                    //4、设置商品的随机码（防止恶意攻击）
                    redisTo.setRandomCode(token);

                    //序列化json格式存入Redis中
                    String seckillValue = JSON.toJSONString(redisTo);
                    operations.put(seckillSkuVo.getPromotionSessionId().toString() + "_" + seckillSkuVo.getSkuId().toString(),seckillValue);
                    //如果当前这个场次的商品库存信息已经上架就不需要上架
                    //5、使用库存作为分布式Redisson信号量（限流）
                    // 使用库存作为分布式信号量
                    RSemaphore semaphore = redissonClient.getSemaphore(SKU_STOCK_SEMAPHORE + token);
                    // 商品可以秒杀的数量作为信号量
                    semaphore.trySetPermits(seckillSkuVo.getSeckillCount());
                }
            });
        });
    }

//    @SentinelResource(value = "getCurrentSeckillSkusResource", blockHandler = "blockHandler", fallbackClass = FallbackClass.class)
    @SentinelResource(value = "getCurrentSeckillSkusResource")
    @Override
    public List<SeckillSkuRedisTo> getCurrentSeckillSkus() {
//        try(Entry entry = SphU.entry("SeckillSkus")){
        //1、确定当前属于哪个秒杀场次
        long currentTime = System.currentTimeMillis();

        //从Redis中查询到所有key以seckill:sessions开头的所有数据
        Set<String> keys = redisTemplate.keys(SESSION__CACHE_PREFIX + "*");
        for (String key : keys) {
            //seckill:sessions:1594396764000_1594453242000
            String replace = key.replace(SESSION__CACHE_PREFIX, "");
            String[] s = replace.split("_");
            //获取存入Redis商品的开始时间
            long startTime = Long.parseLong(s[0]);
            //获取存入Redis商品的结束时间
            long endTime = Long.parseLong(s[1]);
            //判断是否是当前秒杀场次
            if (currentTime >= startTime && currentTime <= endTime) {
                //2、获取这个秒杀场次需要的所有商品信息
                List<String> range = redisTemplate.opsForList().range(key, 0, -1);
                BoundHashOperations<String, String, String> hasOps = redisTemplate.boundHashOps(SECKILL_CHARE_PREFIX);
                assert range != null;
                List<String> listValue = hasOps.multiGet(range);
                if (!CollectionUtils.isEmpty(listValue)) {
                    List<SeckillSkuRedisTo> collect = listValue.stream().map(items -> {
                        SeckillSkuRedisTo redisTo = JSON.parseObject(items, SeckillSkuRedisTo.class);
                        // redisTo.setRandomCode(null);当前秒杀开始需要随机码
                        return redisTo;
                    }).collect(Collectors.toList());
                    return collect;
                }
                break;
            }
        }
         return null;
//        }catch (BlockException e){
//            log.error("SeckillSkus被流控"+e.getMessage());
//        }
//        return null;
    }

    public List<SeckillSkuRedisTo> blockHandler() {
        log.error("请求降级");
        return Lists.newArrayList();
    }

    @Override
    public SeckillSkuRedisTo getSkuSeckillInfo(Long skuId) {
        // 找到所有参与秒杀的商品key
        BoundHashOperations<String, String, String> hashOps = redisTemplate.boundHashOps(SECKILL_CHARE_PREFIX);

        Set<String> keys = hashOps.keys();
        // 6-4
        String regx = "\\d_"+skuId;

        if (!CollectionUtils.isEmpty(keys)){

            for (String key : keys) {
                if(Pattern.matches(regx, key)){
                    String s = hashOps.get(key);
                    SeckillSkuRedisTo redisTo = JSON.parseObject(s, SeckillSkuRedisTo.class);

                    long now = new Date().getTime();
                    if(now>=redisTo.getStartTime() && now<= redisTo.getEndTime()){
                        return redisTo;
                    }else{
                        redisTo.setRandomCode(null);
                        return redisTo;
                    }
                }
            }
        }
        return null;
    }

    @Override
    public String kill(String killId, String rcode, Integer num) throws InterruptedException {

        //获取当前用户的信息
        UmsMemberTo user = SeckillInterceptor.loginUser.get();

        //1、获取当前秒杀商品的详细信息从Redis中获取
        BoundHashOperations<String, String, String> hashOps = redisTemplate.boundHashOps(SECKILL_CHARE_PREFIX);
        String skuInfoStr = hashOps.get(killId);
        if (StringUtils.isEmpty(skuInfoStr)) {
            return null;
        }
        //(合法性效验)
        SeckillSkuRedisTo skuRedisTo = JSON.parseObject(skuInfoStr, SeckillSkuRedisTo.class);
        Long startTime = skuRedisTo.getStartTime();
        Long endTime = skuRedisTo.getEndTime();
        long currentTime = System.currentTimeMillis();
        //判断当前这个秒杀请求是否在活动时间区间内(效验时间的合法性)
        if (currentTime >= startTime && currentTime <= endTime) {
            //2、效验随机码和商品id
            String randomCode = skuRedisTo.getRandomCode();
            String skuId = skuRedisTo.getPromotionSessionId() + "-" +skuRedisTo.getSkuId();
            if (randomCode.equals(rcode) && killId.equals(skuId)) {
                //3、验证购物数量是否合理和库存量是否充足
                Integer seckillLimit = skuRedisTo.getSeckillLimit();
                //获取信号量
                String seckillCount = redisTemplate.opsForValue().get(SKU_STOCK_SEMAPHORE + randomCode);
                Integer count = Integer.valueOf(seckillCount);
                //判断信号量是否大于0,并且买的数量不能超过库存
                if (count > 0 && num <= seckillLimit && count > num ) {
                    //4、验证这个人是否已经买过了（幂等性处理）,如果秒杀成功，就去占位。userId-sessionId-skuId
                    //SETNX 原子性处理
                    String redisKey = user.getId() + "_" + skuId;
                    //设置自动过期(活动结束时间-当前时间)
                    Long ttl = endTime - currentTime;
                    Boolean aBoolean = redisTemplate.opsForValue().setIfAbsent(redisKey, num.toString(), ttl, TimeUnit.MILLISECONDS);
                    if (aBoolean) {
                        //占位成功说明从来没有买过,分布式锁(获取信号量-1)
                        RSemaphore semaphore = redissonClient.getSemaphore(SKU_STOCK_SEMAPHORE + randomCode);
                        // 秒杀成功，快速下单
                        boolean semaphoreCount = semaphore.tryAcquire(num, 100, TimeUnit.MILLISECONDS);
                        //保证Redis中还有商品库存
                        if (semaphoreCount) {
                            //创建订单号和订单信息发送给MQ
                            // 秒杀成功 快速下单 发送消息到 MQ 整个操作时间在 10ms 左右
                            String timeId = IdWorker.getTimeId();
                            SeckillOrderTo orderTo = new SeckillOrderTo();
                            orderTo.setOrderSn(timeId);
                            orderTo.setMemberId(user.getId());
                            orderTo.setNum(num);
                            orderTo.setPromotionSessionId(skuRedisTo.getPromotionSessionId());
                            orderTo.setSkuId(skuRedisTo.getSkuId());
                            orderTo.setSeckillPrice(skuRedisTo.getSeckillPrice());
                            rabbitTemplate.convertAndSend("order-event-exchange","order.seckill.order", orderTo);
                            return timeId;
                        }
                    }
                }
            }
        }
        return null;
    }
}
